Data driving device and data processing device operating in low power mode

ABSTRACT

A data driving device and a data processing device may reduce the amount of consumed power by being standing by for data transmission or data reception in a low-power mode.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority from Republic of Korea PatentApplication No. 10-2020-0027178, filed on Mar. 4, 2020, which is herebyincorporated by reference in its entirety.

BACKGROUND 1. Field of Technology

The present disclosure relates to a data driving device and a dataprocessing device which operate in a low-power mode.

2. Description of the Prior Art

A display device may include a panel and a panel driving device thatdrives the panel. The panel may include a plurality of pixels, which aredisposed alongside each other in the vertical direction and thehorizontal direction and form a matrix, and the plurality of disposedpixels may be located, like a matrix, on a panel.

The panel driving device may drive the pixels of the panel. The paneldriving device may include a data driving device and a data processingdevice. The data driving device may determine a data voltage dependingon image data, and may provide the data voltage to the pixels so as todrive the panel. The data processing device may receive image data froma host, may process the image data so that the data driving devicedetermines a data voltage, and may transmit the processed image data tothe data driving device. The image data is transmitted as a digitalvalue, and the data driving device may convert the image data into ananalog voltage so as to drive each pixel.

The image data may be transmitted from the data processing device to thedata driving device. Here, the data processing device may be atransmission end and the data driving device may be a reception end.Here, in order to receive the image data, the data driving device, whichis the reception end, may always operate so as to receive a signal. Thatis, the data driving device may always consume power since the datadriving device needs to be standing by for receiving image data. Thismay cause the reception end to consume power. In the same manner, inorder to transmit image data, the data processing device, which is thetransmission end, may always operate so as to transmit a signal. Thatis, the data processing device may always consume power since the dataprocessing device needs to be standing by for transmitting image data.This may cause the transmission end to consume power.

SUMMARY

Therefore, the embodiments are to provide a technology associated withan operation method that reduces the amount of power consumed by thedata driving device, which is the reception end, and the data processingdevice, which is the transmission end.

An aspect of the embodiments is to provide a data driving device that isstanding by for data reception in a low-power mode, and a dataprocessing device that is standing by for data transmission in alow-power mode.

Another aspect of the embodiment is to provide a data driving device anda data processing device that enters a low-power mode or a normal modedepending on a wakeup-on signal or a wakeup-off signal.

In accordance with an aspect of the present disclosure, a data drivingdevice which receives data may include: a control circuit configured tooperate in a low-power mode while reception of the data is notperformed, to enter a normal mode so as to receive the data, and toenter the low-power mode again when the reception of the data iscomplete; a training circuit configured to train a signal including atest clock in the normal mode; and a receiving circuit configured toreceive the data when the training is complete.

In the device, the control circuit may maintain the low-power mode whilenot receiving the data, may enter the normal mode when the reception ofthe data begins, may maintain the normal mode until the reception of thedata is complete, and may enter the low-power mode again when thereception of the data is complete.

In the device, the training circuit may produce a lock-on signalindicating that training of the test clock is complete, or a lock-offsignal indicating unlocking, and performs training again when producingthe lock-off signal.

In the device, the control circuit may enter the low-power mode whilenot receiving the data upon receiving a wakeup-on signal, and may enterthe normal mode from the low-power mode upon receiving a wakeup-offsignal.

In the device, the wakeup-on signal and the wakeup-off signal mayinclude a plurality of logic levels different from each other, and maybe transmitted in a single communication line, and the data may be aclock-embedded differential signal and may be transmitted via aplurality of communication lines.

In the device, the receiving circuit may perform communication accordingto a differential scheme via two communication lines in the normal mode,and may receive a logic level signal via one of the two communicationlines in the low-power mode.

In the device, the receiving circuit may transmit an embedded clock viathe two communication lines in the normal mode, may include a clockrecovery circuit for recovering the embedded clock, and may drive theclock recovery circuit using a low power in the low-power mode.

In the device, when data corresponding to an amount of one frame isreceived in the normal mode, the control circuit may determine that datareception is completed, and may enter the low-power mode again.

In accordance with another aspect of the present disclosure, a dataprocessing device which transmits data, may include: a control circuitconfigured to operate in a low-power mode while transmission of the datais not performed, to enter a normal mode in order to transmit the data,and to enter the low-power mode again when the transmission of the datais complete; a receiving circuit configured to receive a result oftraining of a signal including a test clock in the normal mode; and atransmitting circuit configured to transmit the data in the normal mode.

In the device, the control circuit may maintain the low-power mode whilenot transmitting the data, may enter the normal mode when thetransmission of the data begins, may maintain the normal mode until thetransmission of the data is complete, and may enter the low-power modeagain when the transmission of the data is complete.

In the device, the transmitting circuit may perform communicationaccording to a differential scheme via two communication lines in thenormal mode, and may transmit a logic level signal via one of the twocommunication lines in the low-power mode.

In the device, the control circuit may enter the low-power mode whilenot transmitting the data upon receiving a wakeup-on signal, and mayenter the normal mode from the low-power mode upon receiving awakeup-off signal.

In the device the wakeup-on signal and the wakeup-off signal may includea plurality of logic levels different from each other, and may betransmitted via a single communication line, and the data may be aclock-embedded differential signal, and may be transmitted via aplurality of communication lines.

In the device, the transmitting circuit may transmit a signal thatenables or disables a low-power mode of the data driving device.

In the device, the training result may include a lock-on signalindicating that training of the test clock is complete or a lock-offsignal indicating unlocking, and if the training result includes thelock-off signal, the receiving circuit may receive a training resultagain.

According to the above-described embodiments, the data driving deviceand the data processing device may be standing by for data transmissionor reception in a low-power mode and may reduce the amount of powerconsumed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating the configuration of a display deviceaccording to an embodiment;

FIG. 2 is a diagram illustrating the configuration of a data drivingdevice and a data processing device according to an embodiment;

FIG. 3 is a state diagram illustrating operation of a data drivingdevice according to an embodiment;

FIG. 4 is a flowchart illustrating operation of a data driving deviceaccording to an embodiment;

FIG. 5 is a state diagram illustrating operation of a data processingdevice according to an embodiment;

FIG. 6 is a flowchart illustrating operation of a data processing deviceaccording to an embodiment; and

FIG. 7 is a diagram illustrating a signal transmitted or receivedbetween a data driving device and a data processing device according toan embodiment.

DETAILED DESCRIPTION

FIG. 1 is a diagram illustrating the configuration of a display device100 according to an embodiment.

Referring to FIG. 1, a display device 100 may include a panel 110, adata driving device 120, a gate driving device 130, a data processingdevice 140, and the like.

In the panel 110, a plurality of data lines (DL) and a plurality of gatelines (GL) may be disposed, and a plurality of pixels may be disposed. Apixel may include a plurality of sub-pixels. Here, a sub-pixel may bered (R), green (G), blue (B), white (W), and the like. A single pixelmay include sub-pixels (SP) of RGB, SPs of RGBG, SPs of RGBW, or thelike. Hereinafter, for ease of description, it is illustrated that asingle pixel includes sub-pixels of RGB.

The data driving device 120, the gate driving device 130, and the dataprocessing device 140 may be devices which produce signals in order todisplay an image on the panel 110.

The gate driving device 130 may supply a gate driving signal of aturn-on voltage or a turn-off voltage to a gate line (GL). If a gatedriving signal of a turn-on voltage is supplied to a sub-pixel (SP), thesub-pixel (SP) is connected to a data line (DL). If a gate drivingsignal of a turn-off voltage is supplied to a sub-pixel (SP), theconnection between the sub-pixel (SP) and the data line (DL) isdisconnected. The gate driving device 130 may be referred to as a gatedriver.

The data driving device 120 may supply a data voltage (Vdata) to asub-pixel (SP) via a data line (DL). The data voltage (Vdata) suppliedvia the data line (DL) may be supplied to a sub-pixel (SP) according toa gate driving signal. The data driving device 120 may be referred to asa source driver.

The data driving device 120 may produce a plurality of gamma voltages,and may output a data voltage (Vdata) corresponding to image data (RGB)among the plurality of gamma voltages. The data driving device 120 mayinclude a digital-analog converter and a buffer. In response to theimage data (RGB), the digital-analog converter may select one of theplurality of gamma voltages, and may output the one selected voltage tothe buffer. The buffer may amplify the one selected voltage and mayprovide a data voltage (Vdata) to a sub-pixel (SP) via a data line (DL).

The data driving device 120 may include at least one integrated circuit,and the at least one integrated circuit may be connected to a bondingpad of the panel 110 in a manner of a tape automated bonding (TAB) typeor a chip on glass (COG) type, may be directly disposed on the panel110, or may be integrated with the panel 110 depending on an embodiment.In addition, the data driving device 120 may be implemented in a mannerof a chip on film (COF) type.

The data processing device 140 may supply a control signal to the gatedriving device 130 and the data driving device 120. For example, thedata processing device 140 may transmit a gate control signal (GCS),which enables scanning, to the gate driving device 130. The dataprocessing device 140 may output image data to the data driving device120. In addition, the data processing device 140 may transmit a datacontrol signal which performs control so that the data driving device120 supplies a data voltage (Vdata) to each sub-pixel (SP). The dataprocessing device 140 may be referred to as a timing control circuit.

FIG. 2 is a diagram illustrating the configuration of a data drivingdevice 120 and a data processing device 140 according to an embodiment.

Referring to FIG. 2, the data driving device 120 may include a trainingcircuit 221, a control circuit 222, a receiving circuit 223, and atransmitting circuit 224.

The control circuit 222 of the data driving device 120 may operate in alow-power mode while not receiving image data. Subsequently, the controlcircuit 222 may enter a normal mode from the low-power mode, in order toreceive image data. When the reception of the image data is complete,the control circuit 222 may enter the low-power mode again.

Upon receiving a wakeup-on signal, the control circuit 222 may enter thelow-power mode from an off-mode. Upon receiving a wakeup-off signal, thecontrol circuit 222 may enter the normal mode from the low-power mode.

Here, the off-mode may be the state in which power is not supplied tothe data driving device 120 and the data driving device 120 is turnedoff, or may be the state in which only power which enables the minimumoperation of the data driving device 120 is supplied before high-speedimage data reception.

A wakeup-on signal may enable the data driving device 120 in theoff-mode to operate in the low-power mode. A wakeup-off signal mayenable the data driving device 120 in the low-power mode to operate inthe normal mode. The wakeup-on signal and the wakeup-off signal may bedifferent logic level signals, for example, a high-level signal with ahigh voltage or a low-level signal with a low voltage. The wakeup-onsignal and the wakeup-off signal may be transmitted via a singlecommunication line.

A logic level signal may be transmitted or received via, for example, acomplementary metal-oxide-semiconductor (CMOS) or a transistor totransistor logic (TTL) circuit.

While a logic level signal is being transmitted or received, a clock forreading a signal may not be transmitted or received.

A wakeup-on signal and a wakeup-off signal for the data driving device120 may be produced by the data processing device 140, and may betransmitted to the data driving device 120. The receiving circuit 223 ofthe data driving device 120 may receive a wakeup-on signal and awakeup-off signal from the data processing device 140.

In addition, when image data corresponding to the amount of one frame isall received in the normal mode, the control circuit 222 may determinethat data reception is complete. In addition, the control circuit 222may enter the low-power mode again.

As described above, the control circuit 222 may operate in the low-powermode while not receiving image data, may enter the normal mode whenreception of image data begins, and may maintain the normal mode untilthe reception of the image data is complete. For example, the controlcircuit 222 may maintain the normal mode from the start of traininguntil reception of the image data is complete. In addition, the controlcircuit 222 may enter the low-power mode again only after the receptionof the image data is complete.

The training circuit 221 may train a signal including a test clock inthe normal mode. The data driving device 120 may receive aclock-embedded image signal corresponding to image data. Beforebeginning reception of image data, the training circuit 221 may identifywhether a clock embedded for a test is normally extracted in a trainingprocess.

The training circuit 221 may produce a lock-on signal if the trainingcircuit 221 completes training associated with a test clock, or mayproduce a lock-off signal indicating unlocking. If the training circuit221 produces a lock-off signal, the training circuit 221 may performtraining again.

The receiving circuit 223 may receive image data. Particularly, thereceiving circuit 223 may receive image data when training associatedwith a test clock is complete.

The transmitting circuit 224 may transmit a training result to thereceiving circuit 243 of the data processing device 140. The trainingresult may include a lock-on signal indicating completion of trainingassociated with the test clock or a lock-off signal indicatingunlocking.

The data processing device 140 may include a control circuit 241, atransmitting circuit 242, and a receiving circuit 243.

The control circuit 241 of the data processing device 140 may operate inthe low-power mode while not transmitting image data. Subsequently, thecontrol circuit 241 may enter the normal mode in order to transmit imagedata. When transmission of image data is complete, the control circuit241 may enter the low-power mode again.

When receiving a wakeup-on signal, the control circuit 222 may enter thelow-power mode from the off-mode. When receiving a wakeup-off signal,the control circuit 222 may enter the normal mode from the low-powermode.

Here, the off-mode may be the state in which power is not supplied tothe data processing device 140 and the data processing device 140 isturned off, or may be the state in which only power which enables theminimum operation of the data processing device 140 is supplied beforehigh-speed image data transmission.

A wakeup-on signal may enable the data processing device 140 in theoff-mode to operate in the low-power mode. A wakeup-off signal mayenable the data processing device 140 in the low-power mode to operatein the normal mode. The wakeup-on signal and the wakeup-off signal maybe different logic level signals, for example, a high-level signal witha high voltage or a low-level signal with a low voltage. The wakeup-onsignal and the wakeup-off signal may be transmitted via a singlecommunication line.

The wakeup-on signal and the wakeup-off signal for the data processingdevice 140 may be produced by the control circuit 241, or may bereceived from an external circuit, for example, a host.

As described above, the control circuit 241 may operate in the low-powermode while not transmitting image data, may enter the normal mode whentransmission of image data begins, and may maintain the normal modeuntil the transmission of the image data is complete. For example, thecontrol circuit 222 may maintain the normal mode from the start ofreceiving a training result until the transmission of the image data iscomplete. In addition, the control circuit 222 may enter the low-powermode again only after the transmission of the image data is complete.

The receiving circuit 243 may receive the training result associatedwith a signal including a test clock from the transmitting circuit 224of the data driving device 120 in the normal mode. The training resultmay include a lock-on signal indicating completion of trainingassociated with the test clock or a lock-off signal indicatingunlocking. If the training result includes a lock-off signal, thereceiving circuit 223 may receive a training result again.

The transmitting circuit 242 may transmit image data in the normal mode.The transmitting circuit 242 may transmit a wakeup-on signal and awakeup-off signal for the data driving device 120 to the receivingcircuit 223 of the data driving device 120.

In addition, the transmitting circuit 242 may transmit a signal thatenables or disables the low-power mode of the data driving device 120.An enable signal or a disable signal may be transmitted, together withimage data including a clock embedded therein, to the data drivingdevice 120.

When comparing an image signal and a logic-level signal, the imagesignal may be transmitted or received according to a differential schemevia two communication lines, and the logic-level signal may betransmitted or received via one of the two communication lines.

The image signal may be transmitted or received in a high speed whencompared to the logic level signal, may have a relatively low signallevel, and may need to transmit or receive a clock for reading data.Conversely, the logic level signal may be transmitted or received in alow speed, may have a relatively high signal level, and may not need totransmit or receive a clock for reading data.

A clock may be transmitted by being embedded in an image signal, and thereceiving circuit 243 of the data driving device 120 may include a clockrecovery circuit for recovering an embedded clock. The data drivingdevice 120 may drive the clock recovery circuit in the normal mode, andmay drive the clock recovery circuit using a low power in the low-powermode, for example, by blocking a driving power of the clock recoverycircuit.

In the case of changing the low-power mode to the normal mode, clocktraining needs to be performed again and thus, a test clock may betransmitted in the initial stage of the normal mode.

FIG. 3 is a state diagram illustrating operation of a data drivingdevice 120 according to an embodiment.

Referring to FIG. 3, the data driving device 120 may operate in each ofan off-mode, a low-power mode, and a normal mode.

If a wakeup-on signal is transmitted in a single communication line inthe off-mode, the data driving device 120 in the off-mode may enter thelow-power mode (WAKEUP-ON).

The data driving device 120 may be always standing by in the low-powermode while not receiving image data (LOW POWER STATE).

If a wakeup-off signal is transmitted in the single communication linein the low-power mode, the data driving device 120 in the low-power modemay enter the normal mode (WAKEUP-OFF).

If the data driving device 120 enters the normal mode, the data drivingdevice 120 may perform training (TRAINING STATE).

If a training result corresponds to lock-on, the data driving device 120may prepare reception of image data. The image data may be aclock-embedded differential signal (RX LOCK=H). The data driving device120 may be standing by for reception of image data (READY STATE).

If unlocking is performed while the data driving device 120 is standingby for reception of image data, the data driving device may performtraining again (RX LOCK=L).

The data driving device 120 may set an internal register in order toreceive image data (CTRS DETECTED). The data driving device 120 may bestanding by for reception of subsequent image data if the data drivingdevice 120 receives image data corresponding to an one line (END ofLINE).

If it is determined that the data driving device 120 completely receivesthe image data (END DETECTED), the data driving device 120 may terminatereception of the image data (END STATE).

If unlocking is performed while the data driving device 120 terminatesthe reception of the image data, the data driving device 120 may performtraining again (RX LOCK=L).

If the image data is all received up to the last line of one frame (ENDOF FRAME), the data driving device 120 may enter again the low-powermode (LOW POWER STATE).

FIG. 4 is a flowchart illustrating operation of a data driving device120 according to an embodiment.

Referring to FIG. 4, the data driving device 120 may operate in alow-power mode while not receiving image data in operation S402.

The data driving device 120 in the low-power mode may enter a normalmode in order to receive image data in operation S404.

The data driving device 120 may perform training of a signal including atest clock in the normal mode in operation S406.

When training is complete, the data driving device 120 may receive imagedata from a data processing device 140 in operation S408.

The data driving device 120 may determine whether unlocking is performedwhile receiving the image data in operation S410. When unlocking isperformed in operation S410 (YES), the data driving device 120 mayperform training again. If unlocking is not performed and the lockedstate is still continued in operation S410 (NO), the data driving device120 may continue to receive the image data.

The data driving device 120 may determine whether the reception of theimage data is complete in operation S412. If the data driving device 120completely receive the image data in operation S412 (YES), the datadriving device 120 may enter the low-power mode again and may reduce theamount of power consumed. When the reception of the image data isincomplete in operation S412 (NO), the data driving device may continueto receive the image data in operation S414.

FIG. 5 is a state diagram illustrating operation of a data processingdevice 140 according to an embodiment.

Referring to FIG. 5, the data processing device 140 may operate in eachof an off-mode, a low-power mode, and a normal mode.

If a wakeup-on signal is transmitted in a single communication line inthe off-mode, the data processing device 140 in the off-mode may enterthe low-power mode (WAKEUP- ON).

The data processing device 140 may be always standing by in thelow-power mode while not receiving image data (LOW POWER STATE).

If the data processing device 140, which is a transmission end, preparestraining, and the data driving device 120, which is a reception end,operates in the normal mode (RX=ON/TX LOCK=H), the data processingdevice 140 may prepare reception of a training result from the datadriving device (TRAINING STATE).

The data processing device 140 may receive a lock-on signal, indicatingcompletion of training performed by the data driving device 120, fromthe data driving device 120. When training is complete, the dataprocessing device 140 may transmit image data to the data driving device120. The image data may be a clock-embedded differential signal (RXLOCK=H).

The data processing device 140 may continue to transmit image data (DATASTATE). When the image data is completely transmitted, the dataprocessing device 140 may terminate the transmission of the image data(DATA DONE/END CONFIG STATE).

If the transmission of the image data is terminated, or the data drivingdevice 120, which is a reception end, is turned off, the data processingdevice 140 may operate in the low-power mode again (DATA TRANSDONE/RX=OFF).

FIG. 6 is a flowchart illustrating operation of a data processing deviceaccording to an embodiment.

Referring to FIG. 6, the data processing device 140 may operate in alow-power mode while not transmitting image data in operation S602.

The data processing device 140 in the low-power mode may enter a normalmode in order to transmit image data in operation S604.

In the normal mode, the data processing device 140 may receive atraining result that the data driving device 120 obtains by training asignal including a test clock, in operation S606.

When training is complete, the data processing device 140 may transmitimage data to the data driving device 120 in operation S608.

The data processing device 140 may determine whether unlocking isperformed while transmitting the image data in operation S610. The dataprocessing device 140 may receive a signal associated with locking fromthe data driving device 120, and may determine whether unlocking isperformed. When unlocking is performed in operation S610 (YES), the dataprocessing device 140 may receive a training result again. If unlockingis not performed and the locked state is still continued in operationS610 (NO), the data processing device 140 may continue to transmit theimage data.

The data processing device 140 may determine whether the transmission ofthe image data is complete in operation S612. If the data processingdevice 140 completely transmits the image data in operation S612 (YES),the data processing device 140 may enter the low-power mode again andmay reduce the amount of power consumed. When the transmission of theimage data is incomplete in operation S612 (NO), the data processingdevice 140 may continue to transmit the image data in operation S614.

FIG. 7 is a diagram illustrating a signal transmitted or receivedbetween a data driving device 120 and a data processing device 140according to an embodiment.

Referring to FIG. 7, a first format (FORMAT_1) is associated with imagedata which is transmitted or received between the data driving device120 and the data processing device 140 conventionally, and a secondformat (FORMAT_2) is associated with image data which is transmitted orreceived between the data driving device 120 and the data processingdevice 140 according to an embodiment. The data processing device 140may transmit a signal, provided in the first format (FORMAT_1) or thesecond format (FORMAT_2), to the data driving device 120.

Conventionally, image data may include a clock embedded therein, asshown in the first format (FORMAT_1). A signal from a clock area (CK) toa dummy area (DM) may be referred to as a clock-embedded differentialsignal (CEDS) (e.g., a clock-embedded signal). The clock area (CK)including a clock may be located in one side of a data area (DATA). Thedummy area (DM) may be located in the other side of the clock area (CK).

According to an embodiment, an enable (EN) signal and a disable (DIS)signal may be added to a CEDS signal, as shown in the second format(FORMAT_2). The enable signal may enable the data driving device tooperate in the low-power mode. Conversely, the disable signal mayterminate the low-power mode, and may enable the data driving device tooperate in the off-mode or the normal mode. Although the enable signaland the disable signal may include a wakeup-on signal or a wakeup-offsignal for the data driving device, the present disclosure is notlimited thereto, and the signals may be independent therefrom and maydetermine the low-power mode of the data driving device.

While particular embodiments and applications have been illustrated anddescribed, it is to be understood that the invention is not limited tothe precise construction and components disclosed herein and thatvarious modifications, changes and variations which will be apparent tothose skilled in the art may be made in the arrangement, operation anddetails of the method and apparatus disclosed herein without departingfrom the spirit and scope of the present disclosure.

What is claimed is:
 1. A data driving device which receives data, thedata driving device comprising: a control circuit configured to operatein a low-power mode while reception of data is not being performed, toenter a normal mode so as to receive the data, and to enter thelow-power mode again when the reception of the data is complete; atraining circuit configured to train a signal including a test clock inthe normal mode; and a receiving circuit configured to receive the datawhen the training is complete.
 2. The data driving device of claim 1,wherein the control circuit maintains the low-power mode while thereception of the data is not being performed, enters the normal modewhen the reception of the data begins, maintains the normal mode untilthe reception of the data is complete, and enters the low-power modeagain when the reception of the data is complete.
 3. The data drivingdevice of claim 1, wherein the training circuit produces a lock-onsignal indicating that training of the test clock is complete, or alock-off signal indicating unlocking, and performs training again whenproducing the lock-off signal.
 4. The data driving device of claim 1,wherein the control circuit enters the low-power mode upon receiving awakeup-on signal while the reception of the data is not being performedand enters the normal mode from the low-power mode upon receiving awakeup-off signal.
 5. The data driving device of claim 4, wherein thewakeup-on signal and the wakeup-off signal respectively comprise aplurality of logic levels that are different from each other and aretransmitted in a single communication line and the data is aclock-embedded differential signal and is transmitted via a plurality ofcommunication lines.
 6. The data driving device of claim 1, wherein thereceiving circuit performs communication in a differential scheme viatwo communication lines in the normal mode and receives a logic levelsignal via one of the two communication lines in the low-power mode. 7.The data driving device of claim 6, wherein the receiving circuittransmits an embedded clock via the two communication lines in thenormal mode, the receiving circuit comprising a clock recovery circuitfor recovering the embedded clock, and drives the clock recovery circuitusing a low power in the low-power mode.
 8. The data driving device ofclaim 1, wherein, when data corresponding to an amount for one frame isreceived in the normal mode, the control circuit determines that datareception is completed and enters the low-power mode again.
 9. A dataprocessing device which transmits data, the data processing devicecomprising: a control circuit configured to operate in a low-power modewhile transmission of data is not being performed, to enter a normalmode in order to transmit the data, and to enter the low-power modeagain when the transmission of the data is complete; a receiving circuitconfigured to receive a result of training of a signal including a testclock in the normal mode; and a transmitting circuit configured totransmit the data in the normal mode.
 10. The data processing device ofclaim 9, wherein the control circuit maintains the low-power mode whilethe transmission of the data is not performed, enters the normal modewhen the transmission of the data begins, maintains the normal modeuntil the transmission of the data is complete, and enters the low-powermode again when the transmission of the data is complete.
 11. The dataprocessing device of claim 9, wherein the transmitting circuit performscommunication in a differential scheme via two communication lines inthe normal mode and transmits a logic level signal via one of the twocommunication lines in the low-power mode.
 12. The data processingdevice of claim 9, wherein the control circuit enters the low-power modeupon receiving a wakeup-on signal while the transmission of the data isnot being performed and enters the normal mode from the low-power modeupon receiving a wakeup- off signal.
 13. The data processing device ofclaim 12, wherein the wakeup-on signal and the wakeup- off signalrespectively comprise a plurality of logic levels that are differentfrom each other and are transmitted via a single communication line, andthe data is a clock-embedded differential signal and is transmitted viaa plurality of communication lines.
 14. The data processing device ofclaim 9, wherein the transmitting circuit transmits a signal thatenables or disables a low-power mode of the data driving device.
 15. Thedata processing device of claim 9, wherein the training result comprisesa lock-on signal indicating training of the test clock is complete or alock-off signal indicating unlocking, and wherein, if the trainingresult comprises the lock-off signal, the receiving circuit receives atraining result again.